In the field of electricity industry, much effort on the research and development of low cost insulating materials has been recently made in order to enhance insulation efficiency, to extend an insulation life and to reduce a weight. Generally, insulating materials made of polymers or insulating materials made of ceramics have been used as electric insulator materials. Polymer materials are light weight but have an inferior insulation property compared to ceramics, and ceramics have an excellent insulation property but, unlike polymers, have disadvantages in terms of lightweightness and flexibility.
Organic polymer materials are generally lighter, are not readily broken compared to inorganic materials, and have received attention as a next generation material in electrical equipment requiring flexibility and lightweightness. In addition, with increased developments and demands for microminiaturized electrical devices, sizes of thin film transistors included in such electrical devices have also been reduced. Recently, organic materials such as polymethyl methacrylate and polystyrene have been studied as insulating materials for thin film transistors using organic materials (organic thin film transistors).
However, such materials have a problem in that the insulation property declines as the thickness is reduced to a certain level or below. In other words, reducing a thickness of an organic insulation layer included in an organic thin film transistor has a problem of increasing leakage current flowing through the organic insulation layer. This leads to a limit in microminiaturizing sizes of organic thin film transistors.
In addition, when an organic insulation layer undergoes insulation breakdown from a momentary application of high voltage to an organic thin film transistor operating at low voltages, there is a problem in that the organic thin film transistor is degenerated.